80 Advanced spatial profiling of tumor microenvironment using Imaging Mass Cytometry™ approach: high-plex analysis of T-cell exhaustion markers for immunotherapy studies

<h3>Background</h3> Understanding intricate interactions within the tumor microenvironment (TME) is critical for advancing immunotherapy and deciphering disease progression mechanisms. The TME comprises a complex milieu of immune cells, stromal components, and tumor cells, each contributing uniquely to tumor development and response to treatment. Of particular interest are immune cells, especially T cells, which can undergo exhaustion – a state characterized by reduced effector functions and sustained expression of inhibitory receptors such as PD-1 and LAG-3. These exhausted T cells often fail to effectively eliminate tumor cells, posing a significant challenge in cancer immunotherapy. In this study, we leverage an Imaging Mass Cytometry (IMC™) approach to comprehensively characterize immune cell populations and investigate the spatial distribution of T-cell exhaustion markers across various cancer types. <h3>Methods</h3> To explore the TME comprehensively, we developed a 40-plus-marker IMC Panel integrating the Human T Cell Exhaustion IMC Panel and the Human Immuno-Oncology IMC Panel. This expanded panel was applied to multiple normal, cancer, and tissue microarray tissue sections, enabling comprehensive profiling of immune cells and their exhaustion status. Our IMC Panel utilizes over 40 metal-tagged antibodies and allows simultaneous detection of multiple biomarkers within a tissue section. This approach overcomes limitations of traditional fluorescence-based methods, including spectral overlap and autofluorescence, while providing high-resolution insights into cellular composition and spatial organization within the TME. IMC data acquisition utilized two complementary workflows: Preview Mode for initial whole tissue assessment and Tissue Mode (TM) for detailed, high-resolution imaging of selected regions of interest. <h3>Conclusions</h3> These findings, which illustrate the spatial heterogeneity and immune landscape of the TME, are essential for developing future prognostic assessments and have the potential to help guide personalized therapeutic strategies in cancer patients. For Research Use Only. Not for use in diagnostic procedures.